In many producing oil wells, substantial quantities or volumes of gas, under considerable pressure, are produced. The gas production in such wells is generally conducted upwardly through the annulus defined by the well casings and the oil production tubings of the well structures and is dispersed through and from the casing heads at and closing the tops of the well casings.
The production or flow of gas in oil wells is oftentimes sufficient in volume and in pressure to interfere with the effective pumping of oil from such wells.
In the past and to assure effective pumping of oil from wells in which substantial volumes of gas is produced, the prior art has provided special production tools arranged at the lower ends of the production tubing to effect desired separation of gas and oil at the bottoms of the wells and to thereby present the oil in a condition in which it can be effectively pumped upwardly through the tubing and from the wells. The above noted tools are commonly referred to as "gas anchors" and are in the nature of sumps or catch basins arranged in the lower ends of the well structures. Gas anchors function to receive the gas and oil flowing from the earth's formation and permit the oil and gas to separate preparatory to pumping and removal of the oil from the wells. The separated gas flows out of the gas anchors and up through the annulus in the wells below the tubings and casings and the separated oil drops and is collected in the basin portions of the anchor structures, from which it can be pumped.
Further, in the case of oil wells which produce notable volumes of gas at substantial pressure, the prior art has sought to use the gas as a motive force to move or assist the movement of oil up through the production tubing. To this end, the prior art has provided production tools which serve or function to introduce gas into production tubings at one or more locations above the lower ends of the tubings to blow and/or urge oil in the tubings upwardly therein and/or to "lighten" the hydrostatic head on the column of oil in the tubing. Such tools are commonly referred to as "gas lifts".
Gas anchors provided by the prior art have taken many different forms which are quite effective to separate the gas and oil in the wells in which they are arranged and to thereby facilitate the pumping and movement of oil from the wells, but do little or nothing more than separate the gas and oil.
Gas lifts provided by the prior art have taken many different forms which are quite effective to move and advance oil upwardly through the production tubing of wells in which they are used. As a rule, the most effective gas lifts are those gas lifts which function to commingle and mix the gas and oil in the production tubings to an extent or to a degree that the production fluids within the tubings can be put into a light, easy-to-move mixture from which the gas does not escape and from which the oil does not settle at an excessive rate, as it is transported or moved upwardly through the production tubing.
As a general rule, gas lifts are positioned in their related strings of production tubing at one or more locations spaced above the lower ends of the tubing strings and above the pumps at the lower ends of the tubing strings. The gas from the wells is conducted up in the well structures through the annulus between the casings and production tubing strings to the gas lifts and is introduced into the tubing strings by the gas lifts. The annuli between the casings and tubing strings are sealed at the tops of the wells by casing heads and in some instances are suitably packed or sealed off adjacent the gas lift tools to effect desired control of the flow of gas in the well structures.